i've heard of others in my area doing it this way, only around here it's more around $500/ zone, not 100% sure if that includes controller and back flow...i've never heard of the $100/head, but that makes sense, each zone is usually 5 heads, for rotors at least

Thats as bad as using google earth to bid jobs by square footage without knowing a water source. I heard a customer ask last week "why is it called a doublecheck?" The answer I heard from the "bidder" in our company was "because it it had one check it would be called a singlecheck" <facepalm>

I really appreciate the input, and I totally agree it does vary by area/site data/etc.
Once again I'm not interested in what you specifically are charging, that's your business not mine. I was mainly looking to see if I could find a point of reference or an average, and I think I have a pretty good feel for it now.